IEEE Std. 802.3ah 1 Gbps EPON (1G-EPON) systems have been deployed to more than 30 million subscribers worldwide and support diverse services, including IPTV, VoIP, and cellular backhaul. The new 802.3av enables seamless upgrades via the simultaneous operation of 1 Gbps and 10 Gbps symmetric and asymmetric EPON systems on the same outside plant. This allows operators to introduce 10G- EPON without replacing any existing 1G-EPON customer equipment and minimizes the operational impact of upgrading a large, in-service FTTH network.